[alsa-devel] Request for Device ID addition : 6935G

[Takashi Iwai]

At Sat, 13 Jun 2009 18:11:15 +0200,
Hector Martin wrote:
> 
> Takashi Iwai wrote:
> > Hector, does it work on your machine?  If yes, there should be a
> > slight difference between 6935G and 8930G...
> Yes, the DMIC works fine here (in mono mode).
> 
> Karthik: please look in sound/pci/hda/patch_realtek.c and locate the
> alc889_acer_aspire_8930g_verbs array. At the end, where it talks about
> the "DMIC fix", find the last verb:
> 
> {0x20, AC_VERB_SET_PROC_COEF, 0x0003},
> 
> And change the value from 0x0003 to 0x0001 and see what that does.
> 
> If this works and you get some audio, make a stereo recording. You want
> both channels to be of equal volume.
> 
> I suspect you have a mono mic on the left channel. I have a stereo
> sum/difference mic (WTF) with sum on the right channel, so I tweaked the
> setting to replicate the right channel to both. This would kill your
> audio if your microphone is just a mono one on the left channel. Setting
> 0x0001 should get you standard stereo audio as it comes from the mic(s).
> I think setting 0x0002 should get you what you want (left channel
> replicated to both channels). If not, try setting 0x0000.
> 
> Takashi: if I'm right, we'll need two model entries instead of one and
> we should probably split off the verb array into three (base, stereo
> sum/dif mic fix, mono mic fix).

Right.  And, IIRC, some other Aspire laptops such as Aspire One have a 
similar problem (the stereo differential from a PDM mic module), it'd
be a good workaround, too.   We need to check that, too...


Takashi